Rothman InstituteCopyright (c) 2015 Thomas Jefferson University All rights reserved.http://jdc.jefferson.edu/rothman_institute
Recent documents in Rothman Instituteen-usTue, 26 May 2015 01:31:17 PDT3600Biological response to prosthetic debris.http://jdc.jefferson.edu/rothman_institute/62
http://jdc.jefferson.edu/rothman_institute/62Sun, 24 May 2015 19:18:56 PDT
Joint arthroplasty had revolutionized the outcome of orthopaedic surgery. Extensive and collaborative work of many innovator surgeons had led to the development of durable bearing surfaces, yet no single material is considered absolutely perfect. Generation of wear debris from any part of the prosthesis is unavoidable. Implant loosening secondary to osteolysis is the most common mode of failure of arthroplasty. Osteolysis is the resultant of complex contribution of the generated wear debris and the mechanical instability of the prosthetic components. Roughly speaking, all orthopedic biomaterials may induce a universal biologic host response to generated wear débris with little specific characteristics for each material; but some debris has been shown to be more cytotoxic than others. Prosthetic wear debris induces an extensive biological cascade of adverse cellular responses, where macrophages are the main cellular type involved in this hostile inflammatory process. Macrophages cause osteolysis indirectly by releasing numerous chemotactic inflammatory mediators, and directly by resorbing bone with their membrane microstructures. The bio-reactivity of wear particles depends on two major elements: particle characteristics (size, concentration and composition) and host characteristics. While any particle type may enhance hostile cellular reaction, cytological examination demonstrated that more than 70% of the debris burden is constituted of polyethylene particles. Comprehensive understanding of the intricate process of osteolysis is of utmost importance for future development of therapeutic modalities that may delay or prevent the disease progression.
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Diana Bitar et al.Increased mean arterial pressure goals after spinal cord injury and functional outcome.http://jdc.jefferson.edu/rothman_institute/61
http://jdc.jefferson.edu/rothman_institute/61Sat, 23 May 2015 13:48:49 PDT
INTRODUCTION: Acute spinal cord injury (SCI) is often treated with induced hypertension to enhance spinal cord perfusion. The optimal mean arterial pressure (MAP) likely varies between patients. Arbitrary goals are often set, frequently requiring vasopressors to achieve, with no clear evidence supporting this practice. We hypothesize that increased MAP goals and episodes of relative hypotension do not affect hospital outcome.

MATERIALS AND METHODS: All cervical and thoracic SCI patients treated at a level one trauma and regional SCI center over at 2.5-year period were retrospectively reviewed. Lowest and average hourly MAP was recorded for the first 72 h of hospitalization, allowing for quantification of mean MAP and the total number of episodic relative hypotensive events. These data were further compared to daily American spinal injury association motor score (AMS), which was used to determine the severity of SCI and improvement/decline during hospitalization. Patient's data were finally analyzed at theoretic MAP set points.

RESULTS: One hundred and five patients had complete data during the study period. At higher theoretic MAP set points (85 and 90), increased number of relative hypotensive episodes correlated with lower admission AMS (85 mmHg: <10 >episodes, AMS 66.2; >50 episodes, 22.0; P < 0.001) and the need for vasopressors (P < 0.03) but showed no statistical change in AMS by hospital discharge. The need for vasopressors correlated with the number of hypotensive episodes and inversely related to admission AMS at all theoretic MAP goal set points but was not correlated with the change in AMS during the hospitalization.

CONCLUSIONS: The frequency of relative hypotension and the need for vasopressors are progressively related to more severe SCI, as denoted by lower admission AMS. However, episodes of hypotension and the need for vasopressors did not affect the change in AMS during the acute hospitalization, regardless of theoretic MAP goal set-point. Arbitrarily elevated MAP goals may not be efficacious.

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Niels D Martin et al.Effectiveness of Surgery for Lumbar Stenosis and Degenerative Spondylolisthesis in the Octogenarian Population: Analysis of the Spine Patient Outcomes Research Trial (SPORT) Data.http://jdc.jefferson.edu/rothman_institute/60
http://jdc.jefferson.edu/rothman_institute/60Mon, 23 Feb 2015 19:02:10 PST
BACKGROUND: The purpose of this study was to determine whether surgery is an effective option for the treatment of stenosis of the lumbar spine and degenerative spondylolisthesis in the octogenarian population.

METHODS: An as-treated analysis of patients with lumbar stenosis and degenerative spondylolisthesis enrolled in the Spine Patient Outcomes Research Trial (SPORT) was performed. Patients who were at least eighty years of age (n = 105) were compared with those younger than eighty years (n = 1130). Baseline patient and clinical characteristics were noted, and the difference in improvement from baseline between operative and nonoperative treatment was determined for each group at each follow-up time period up to four years.

RESULTS: There were no significant baseline differences in the primary or secondary patient-reported clinical outcome measures between the two patient age groups. Patients at least eighty years of age had higher prevalences of multilevel stenosis, severe stenosis, and asymmetric motor weakness. Patients at least eighty years of age also had higher prevalences of hypertension, heart disease, osteoporosis, and joint problems at baseline, but they had a lower body mass index and lower prevalences of depression and smoking. Fifty-eight of the 105 patients at least eighty years of age and 749 of the 1130 younger patients underwent operative management. There were no differences in the rates of intraoperative or postoperative complications, reoperation, or postoperative mortality between the older and younger groups. Averaged over a four-year follow-up period, operatively treated patients at least eighty years of age had significantly greater improvement in all primary and secondary outcome measures compared with nonoperatively treated patients. The treatment effects in patients at least eighty years of age were similar to those in younger patients for all primary and secondary measures except the SF-36 (Short Form-36) bodily pain domain and the percentage who self-rated their progress as a major improvement, in both of which the treatment effect was significantly smaller.

CONCLUSIONS: Operative treatment of lumbar stenosis and degenerative spondylolisthesis offered a significant benefit over nonoperative treatment in patients at least eighty years of age (p < 0.05). There were no significant increases in the complication and mortality rates following surgery in this patient population compared with younger patients (p > 0.05).

LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Evidence Acquisition: Data were obtained from previously published peer-reviewed literature through a search of the entire PubMed database (up to December 2012) as well as from textbook chapters.

Results: Treatment with culture-specific antibiotics and debridement with graft retention is generally more effective than graft removal, but with persistent infection consideration should be given to graft removal. Graft type likely has no effect on infection rates.

Conclusions: The early diagnosis of infection and appropriate treatment are necessary to avoid the complications of articular cartilage damage and arthrofibrosis.

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C. Stucken et al.Leukocyte esterase strip test: matched for musculoskeletal infection society criteria.http://jdc.jefferson.edu/rothman_institute/58
http://jdc.jefferson.edu/rothman_institute/58Mon, 08 Dec 2014 09:50:47 PST
BACKGROUND: The presence of leukocyte esterase in the synovial fluid has recently been proposed as a marker for periprosthetic joint infection. However, the sensitivity and specificity of leukocyte esterase has not been determined when matched for the current, most inclusive Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection.

METHODS: The presence of leukocyte esterase was prospectively evaluated in synovial joint aspirates from hips and knees from May 2009 to May 2013. The cohort consisted of 189 hip and knee aspirations (fifty-two positive and 137 negative for infection). If the aspirate was bloody, a centrifuge was used to precipitate red blood cells and obtain clear synovial fluid. A standard chemical test strip (graded as negative, trace, +, or ++) was used to detect the presence of leukocyte esterase. The sensitivity, specificity, positive predictive value, and negative predictive value of the leukocyte esterase strip test were calculated using ++ and ++/+ as two positive strip result scenarios.

CONCLUSIONS: When matched to the current MSIS criteria, the leukocyte esterase strip test yielded a high specificity, positive predictive value, negative predictive value, and moderate sensitivity. These results demonstrate that leukocyte esterase is an accurate, effective marker of periprosthetic joint infection as defined by the MSIS criteria. The leukocyte esterase strip test is a valuable tool that can be used in conjunction with the current battery of diagnostic tests available.

LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

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Eric H Tischler et al.What's Good for the Heart Is Good for the Shoulder? Commentary on an article by Chang-Meen Sung, MD, et al.: "Are Serum Lipids Involved in Primary Frozen Shoulder? A Case-Control Study".http://jdc.jefferson.edu/rothman_institute/57
http://jdc.jefferson.edu/rothman_institute/57Mon, 08 Dec 2014 08:43:11 PSTMark D LazarusEmerging Multidrug Resistance of Methicillin-Resistant Staphylococcus aureus in Hand Infections.http://jdc.jefferson.edu/rothman_institute/56
http://jdc.jefferson.edu/rothman_institute/56Mon, 27 Oct 2014 17:48:41 PDT
BACKGROUND: Methicillin-resistant Staphylococcus aureus has been the most commonly identified pathogen in hand infections at urban centers, but the evolving antibiotic sensitivity profiles of methicillin-resistant Staphylococcus aureus are not known. The purposes of this study are to determine if multidrug resistance in methicillin-resistant Staphylococcus aureus is emerging and to provide current recommendations for empiric antibiotic selection for hand infections in endemic regions.

METHODS: An eight-year longitudinal, retrospective chart review was performed on all culture-positive hand infections encountered by an urban hospital from 2005 to 2012. The proportions of all major organisms were calculated for each year. Methicillin-resistant Staphylococcus aureus infections were additionally analyzed for antibiotic sensitivity.

CONCLUSIONS: Significant increases in resistance to clindamycin and levofloxacin were observed in recent years, and empiric therapy with these drugs may have limited efficacy, especially in urban centers.

CLINICAL RELEVANCE: Hand infections caused by methicillin-resistant Staphylococcus aureus may be developing increasing resistance to clindamycin and levofloxacin in recent years. This longitudinal study examines the effectiveness of a variety of antibiotics to methicillin-resistant Staphylococcus aureus.

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Rick Tosti et al.Risk factors for surgical site infection following total joint arthroplasty.http://jdc.jefferson.edu/rothman_institute/55
http://jdc.jefferson.edu/rothman_institute/55Sat, 25 Oct 2014 14:22:21 PDT
BACKGROUND: Currently, most hospitals in the United States are obliged to report infections that occur following total joint arthroplasty to the Centers for Disease Control and Prevention through the National Healthcare Safety Network surveillance. The objective of this study was to identify the risk factors of surgical site infections that were reported to the Centers for Disease Control and Prevention from a single institution.

METHODS: For this study, 6111 primary and revision total joint arthroplasties performed from April 2010 to June 2012 were identified. Surgical site infection cases captured by infection surveillance staff on the basis of the Centers for Disease Control and Prevention definition were identified. Surgical site infection cases with index surgery performed at another institution were excluded. All cases were followed up for one year for development of surgical site infection. The model for predictors of surgical site infection was created by logistic regression and was validated by bootstrap resampling.

RESULTS: Of all performed total joint arthroplasties, surgical site infection developed in eighty cases (1.31% [95% confidence interval, 1.02% to 1.59%]). The highest rate of surgical site infection was observed in revision total knee arthroplasty (4.57% [95% confidence interval, 2.31% to 6.83%]) followed by revision total hip arthroplasty (1.94% [95% confidence interval, 0.75% to 3.13%]). Among the variables examined, the predictive factors of surgical site infection were higher Charlson Comorbidity Index (odds ratio for a Charlson Comorbidity Index of ≥2, 2.29 [95% confidence interval, 1.32 to 3.94] and odds ratio for a Charlson Comorbidity Index of 1, 2.09 [95% confidence interval, 1.06 to 4.10]), male sex (odds ratio, 1.79 [95% confidence interval, 1.11 to 2.89]), and revision total knee arthroplasty (odds ratio, 3.13 [95% confidence interval, 1.17 to 8.34]), and a higher level of preoperative hemoglobin (odds ratio, 0.85 per point [95% confidence interval, 0.73 to 0.98 per point]) was protective against surgical site infection. The C-statistic of the model was 0.709 without correction and 0.678 after bootstrap correction, indicating that the model has fair predictive power.

CONCLUSIONS: Low preoperative hemoglobin level is one of the risk factors for surgical site infection and preoperative correction of hemoglobin may reduce the likelihood of postoperative surgical site infection.

LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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Mohammad R Rasouli et al.A Survey of Expert Opinion Regarding Rotator Cuff Repair.http://jdc.jefferson.edu/rothman_institute/54
http://jdc.jefferson.edu/rothman_institute/54Sat, 06 Sep 2014 14:58:52 PDT
Many patients with rotator cuff tears have questions for their surgeons regarding the surgical procedure, perioperative management, restrictions, therapy, and ability to work after a rotator cuff repair. The purpose of our study was to determine common clinical practices among experts regarding rotator cuff repair and to assist them in counseling patients. We surveyed 372 members of the American Shoulder and Elbow Surgeons (ASES) and the Association of Clinical Elbow and Shoulder Surgeons (ACESS); 111 members (29.8%) completed all or part of the survey, and 92.8% of the respondents answered every question. A consensus response (>50% agreement) was achieved on 49% (24 of 49) of the questions. Variability in responses likely reflects the fact that clinical practices have evolved over time based on clinical experience.
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Daniel C Acevedo et al.Operative management of partial-thickness tears of the proximal hamstring muscles in athletes.http://jdc.jefferson.edu/rothman_institute/53
http://jdc.jefferson.edu/rothman_institute/53Tue, 19 Aug 2014 06:25:36 PDT
BACKGROUND: Partial tears of the hamstring muscle origin represent a challenging clinical problem to the patient and orthopaedic surgeon. Although nonoperative treatment is frequently met with limited success, there is a paucity of data on the efficacy of surgical management for partial proximal hamstring tears in the active and athletic population.

PURPOSE: To evaluate the results of an anatomic repair for partial tears of the hamstring muscle origin in athletes.

STUDY DESIGN: Case series; Level of evidence, 4.

METHODS: The records of 17 patients with partial tears of the proximal hamstring origin were reviewed after institutional review board approval was obtained. All patients were treated with open debridement and primary tendon repair after failure of at least 6 months of nonoperative therapy. Clinical and operative records, radiographs, and magnetic resonance images were reviewed for all patients. A patient-reported outcomes survey was completed by 14 patients that included the Lower Extremity Functional Score (LEFS), Marx activity rating scale, custom LEFS and Marx scales, and subjective patient satisfaction scores. Early and late postoperative complications were recorded.

RESULTS: There were 3 male and 14 female patients; their average age was 43 years (range, 19-64 years) and average follow-up was 32 months (range, 12-51 months). There were 2 collegiate athletes (field hockey, track), 14 amateur athletes (distance running, waterskiing, tennis), and a professional bodybuilder. Postoperative LEFS was 73.3 ± 9.9 (range, 50-80) and custom LEFS was 66.7 ± 17.0 (range, 37-80) of a maximum 80 points. The most commonly reported difficulty was with prolonged sitting and explosive direction change while running. The average Marx score was 6.5 ± 5.3 (range, 0-16) of a maximum 16, correlating with a greater return to recreational running activities in this patient cohort than regular participation in pivoting or cutting sports. Marx custom scores were 20 of a maximum 20 in all patients, demonstrating no disability in the operative extremity with activities of daily living. No patient underwent a subsequent surgery. One patient was not satisfied with the result and reported persistent symptoms during competitive distance running. All patients were able to return to their preoperative level of activity after surgery.

CONCLUSION: Anatomic surgical treatment of partial proximal hamstring avulsions can lead to satisfactory functional outcomes, a high rate of return to athletic activity, and low complication rate. This procedure should be reserved for patients who have failed an extended course of nonoperative treatment, and the proximity of the sciatic nerve mandates a careful assessment of the risk-benefit ratio before surgery is undertaken.

METHODS: Consecutive patients undergoing total hip arthroplasty under spinal anesthesia were randomized to treatment with or without insertion of an indwelling urinary catheter. All patients received spinal anesthesia with 15 to 30 mg of 0.5% bupivacaine. The catheter group was subjected to a standard postoperative protocol, with removal of the indwelling catheter within forty-eight hours postoperatively. The experimental group was monitored for urinary retention and, if necessary, had straight catheterization up to two times prior to the placement of an indwelling catheter.

RESULTS: Two hundred patients were included in the study. There was no significant difference between the two groups in terms of the prevalence of urinary retention, the prevalence of urinary tract infection, or the length of stay. Nine patients in the no-catheter group and three patients in the catheter group (following removal of the catheter) required straight catheterization because of urinary retention. Three patients in the catheter group and no patient in the no-catheter group had development of urinary tract infection.

CONCLUSIONS: Patients undergoing total hip arthroplasty under spinal anesthesia appear to be at low risk for urinary retention. Thus, a routine indwelling catheter is not required for such patients.

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Adam G Miller, MD et al.AdultAgedAged, 80 and overAnesthesia, SpinalArthroplasty, Replacement, HipFemaleHumansLength of StayMaleMiddle AgedPostoperative PeriodPrevalenceProspective StudiesUrinary CatheterizationUrinary CathetersUrinary RetentionUrinary Tract InfectionsThe effect of malnutrition on patients undergoing elective joint arthroplasty.http://jdc.jefferson.edu/rothman_institute/51
http://jdc.jefferson.edu/rothman_institute/51Tue, 22 Jul 2014 07:21:05 PDT
Malnutrition has been linked to serious complications in patients undergoing elective total joint arthroplasty (TJA). This study prospectively evaluated 2,161 patients undergoing elective TJA for malnutrition as defined by either an abnormal serum albumin or transferrin. The overall incidence of malnutrition was 8.5% (184 of 2,161) and the rate of overall complications in the malnourished group was 12% as compared to 2.9% in patients with normal parameters (P55years-old undergoing TJA and is associated with a significant increase in post-operative complications.
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Ronald Huang, MD et al.AdolescentAdultAgedAged, 80 and overArthroplasty, ReplacementArthroplasty, Replacement, HipBiological MarkersCohort StudiesFemaleHematomaHumansIncidenceMaleMalnutritionMiddle AgedObesityPostoperative ComplicationsPrevalenceProspective StudiesSerum AlbuminSurgical Wound InfectionTransferrinYoung AdultWhat's New in Spine Surgery.http://jdc.jefferson.edu/rothman_institute/50
http://jdc.jefferson.edu/rothman_institute/50Sun, 20 Jul 2014 13:59:43 PDTKeith H Bridwell et al.Definition of Periprosthetic Joint Infectionhttp://jdc.jefferson.edu/rothman_institute/49
http://jdc.jefferson.edu/rothman_institute/49Thu, 10 Jul 2014 12:47:43 PDT
Diagnosis of periprosthetic joint infection (PJI) remains challenging as no “gold standard” for diagnosis exists [3]. The challenge is then what test(s) or criterion (ia) can be used to define PJI. In an effort to standardize the definition of PJI, Musculoskeletal Infection Society (MSIS) convened a workgroup in 2011 to issue diagnostic criteria for PJI [1]. The MSIS definition of PJI consists of two major criteria, when the presence of either criterion would indicate PJI, and six minor criteria, when the presence of four or more would indicate PJI.
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Javad Parvizi, MD, FRCS et al.The impact of patellar resurfacing in two-stage revision of the infected total knee arthroplasty.http://jdc.jefferson.edu/rothman_institute/48
http://jdc.jefferson.edu/rothman_institute/48Thu, 10 Jul 2014 12:35:30 PDT
Evidence for optimal management of the patellofemoral joint in revision surgery for the infected TKA is limited. We reviewed 69 infected TKAs undergoing two-stage revision. Fifty four patellae were resurfaced, 11 had patelloplasty performed, two were augmented with trabecular metal, one had impaction grafting, and one knee underwent patellectomy. Average follow-up was 4.5years. The patients that received patellar resurfacing at re-implantation experienced statistically significant improvements in KSS pain score, functional KSS, and patellar score (P
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Aaron Glynn et al.Aquacel Surgical Dressing Reduces the Rate of Acute PJI Following Total Joint Arthroplasty: A Case-Control Study.http://jdc.jefferson.edu/rothman_institute/47
http://jdc.jefferson.edu/rothman_institute/47Wed, 11 Jun 2014 08:05:43 PDT
An effort to prevent PJI has led to the development of antimicrobial dressings that support wound healing. We sought to determine whether Aquacel Surgical dressing independently reduces the rate of acute PJI following TJA. A single institution retrospective chart review of 903 consecutive cases who received the Aquacel Surgical dressing and 875 consecutive cases who received standard gauze dressing was conducted to determine the incidence of acute PJI (within 3months). The incidence of acute PJI is 0.44% in the Aquacel dressing group compared to 1.7% in the standard gauze dressing group (P=0.005). Multivariate analysis revealed that use of Aquacel dressing was an independent risk factor for reduction of PJI (odds ratio of 0.165, 95% confidence interval: 0.051-0.533). Aquacel Surgical dressing significantly reduces the incidence of acute PJI.
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Jenny Cai et al.Nanotechnology: current concepts in orthopaedic surgery and future directions.http://jdc.jefferson.edu/rothman_institute/46
http://jdc.jefferson.edu/rothman_institute/46Tue, 03 Jun 2014 19:08:59 PDT
Nanotechnology is the study, production and controlled manipulation of materials with a grain size < 100 nm. At this level, the laws of classical mechanics fall away and those of quantum mechanics take over, resulting in unique behaviour of matter in terms of melting point, conductivity and reactivity. Additionally, and likely more significant, as grain size decreases, the ratio of surface area to volume drastically increases, allowing for greater interaction between implants and the surrounding cellular environment. This favourable increase in surface area plays an important role in mesenchymal cell differentiation and ultimately bone-implant interactions. Basic science and translational research have revealed important potential applications for nanotechnology in orthopaedic surgery, particularly with regard to improving the interaction between implants and host bone. Nanophase materials more closely match the architecture of native trabecular bone, thereby greatly improving the osseo-integration of orthopaedic implants. Nanophase-coated prostheses can also reduce bacterial adhesion more than conventionally surfaced prostheses. Nanophase selenium has shown great promise when used for tumour reconstructions, as has nanophase silver in the management of traumatic wounds. Nanophase silver may significantly improve healing of peripheral nerve injuries, and nanophase gold has powerful anti-inflammatory effects on tendon inflammation. Considerable advances must be made in our understanding of the potential health risks of production, implantation and wear patterns of nanophase devices before they are approved for clinical use. Their potential, however, is considerable, and is likely to benefit us all in the future. Cite this article: Bone Joint J 2014; 96-B: 569-73.
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M P Sullivan et al.Revision total knee arthroplasty in the young patient: is there trouble on the horizon?http://jdc.jefferson.edu/rothman_institute/45
http://jdc.jefferson.edu/rothman_institute/45Tue, 06 May 2014 07:17:18 PDT
BACKGROUND: The volume of total knee arthroplasties, including revisions, in young patients is expected to rise. The objective of this study was to compare the reasons for revision and re-revision total knee arthroplasties between younger and older patients, to determine the survivorship of revision total knee arthroplasties, and to identify risk factors associated with failure of revision in patients fifty years of age or younger.

METHODS: Perioperative data were collected for all total knee arthroplasty revisions performed from August 1999 to December 2009. A cohort of eighty-four patients who were fifty years of age or younger and a cohort of eighty-four patients who were sixty to seventy years of age were matched for the date of surgery, sex, and body mass index (BMI). The etiology of failure of the index total knee arthroplasty and all subsequent revision total knee arthroplasties was determined. Kaplan-Meier survival curves were used to evaluate the timing of the primary failure and the survivorship of revision knee procedures. Finally, multivariate Cox regression was used to calculate risk ratios for the influence of age, sex, BMI, and the reason for the initial revision on survival of the revision total knee arthroplasty.

RESULTS: The most common reason for the initial revision was aseptic loosening (27%; 95% confidence interval [CI] = 19% to 38%) in the younger cohort and infection (30%; 95% CI = 21% to 40%) in the older cohort. Of the twenty-five second revisions in younger patients, 32% (95% CI = 17% to 52%) were for infection, whereas 50% (95% CI = 32% to 68%) of the twenty-six second revisions in the older cohort were for infection. Cumulative six-year survival rates were 71.0% (95% CI = 60.7% to 83.0%) and 66.1% (95% CI = 54.5% to 80.2%) for revisions in the younger and older cohorts, respectively. Infection and a BMI of ≥40 kg/m2 posed the greatest risk of failure of revision procedures, with risk ratios of 2.731 (p = 0.006) and 2.934 (p = 0.009), respectively.

CONCLUSIONS: The survivorship of knee revisions in younger patients is a cause of concern, and the higher rates of aseptic failure in these patients may be related to unique demands that they place on the reconstruction. Improvement in implant fixation and treatment of infection when these patients undergo revision total knee arthroplasty is needed.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

METHODS: Four hundred and thirty-six patients with at least one surgical intervention secondary to confirmed periprosthetic joint infection were compared with 2342 patients undergoing revision arthroplasty for aseptic failure. The incidence of mortality at thirty days, ninety days, one year, two years, and five years after surgery was assessed. Multivariate analysis was used to assess periprosthetic joint infection as an independent predictor of mortality. In the periprosthetic joint infection population, variables investigated as potential risk factors for mortality were evaluated.

RESULTS: Mortality was significantly greater (p < 0.001) in patients with periprosthetic joint infection compared with those undergoing aseptic revision arthroplasty at ninety days (3.7% versus 0.8%), one year (10.6% versus 2.0%), two years (13.6% versus 3.9%), and five years (25.9% versus 12.9%). After controlling for age, sex, ethnicity, number of procedures, involved joint, body mass index, and Charlson Comorbidity Index, revision arthroplasty for periprosthetic joint infection was associated with a fivefold increase in mortality compared with revision arthroplasty for aseptic failures. In the periprosthetic joint infection population, independent predictors of mortality included increasing age, higher Charlson Comorbidity Index, history of stroke, polymicrobial infections, and cardiac disease.

CONCLUSIONS: Although it is well known that periprosthetic joint infection is a devastating complication that severely limits joint function and is consistently difficult to eradicate, surgeons must also be cognizant of the systemic impact of periprosthetic joint infection and its major influence on fatal outcome in patients.

Adoption of a new technology in surgery today is subject to assessment by many stakeholders. These include surgeons, patients, hospitals, regulators, and payers. The fundamental tool for assessment is the determination of “value.” But value has different meanings for each of the stakeholders. The usual definition of value is “outcome divided by cost.” Although cost is usually measured in dollars, the measures for “outcome” are not clearly defined nor agreed upon. What follows is an attempt to define the value of robotic surgery in joint replacement surgery for each of the stakeholders.

First, however, we need to understand that the primary value of robotics in joint replacement is the reduction of human error by improving accuracy and precision. This is the same value that has resulted in adoption of robotics in most manufacturing processes. A major part of quality control in manufacturing is optimizing accuracy and precision by reducing human error. Surgery, however, is a blend of intelligence, art, and skill. There are many human skills that are poorly performed by robots and vice versa. The appropriate use of robotics in joint replacement surgery is intended to improve the accuracy and precision of implant selection and placement as well as execution by bone preparation. The goal is not to replace the surgeon but to enhance the surgeon's performance. Robotics offers a tool that enables the surgeon to reproduce his/her best performance on a consistent basis.